Reinforced needleed pile fabric of potentially adhesive multi-component fibers and method of making the same



C. R SISSO FILE FABRIC Oct. 17, 1967" Y NS 3,347,736 REINFORCED NEEDLED OF POTENTIALLY ADHESIVE MULTI'COMPONENT FIBERS AND METHOD OF MAKING THE SAME Filed NOV. 27, 19

Invenlor United States latent ()1 3,347,736 REINFORCED NEEDLED PHLE FABRHC F PDTEN- TIALLY ADHESIVE MULTI-CUMPQNEN'I FHBERS AND METHOD OF MAKING THE SAME Christopher Robert Sissons, Raglan, England, assignor to British Nylon Spinners Limited, Pontypool, Monmouthshire, England Filed Nov. 27, 1964, Ser. No. 414,243 Claims priority, application Great Britain, Nov. 29, 1963, 47,218/63 16 Claims. (Cl. 161-67) This invention relates to making the same.

The principal object of this invention expressed in general terms is to provide, by a technique involving the needling of a fibrous web, pile fabrics.

More specifically, an object of this invention is to provide, by a technique involving the needling of a fibrous web, pile fibres having a well-developed dimensional stability and tensile strength.

A further object of this invention is to provide methods of making, from fibrous webs, pile fabrics having a welldeveloped dimensional stability and tensile strength.

These and still other objects of this invention will be apparent from the following detailed description.

Thus, according to one aspect of this invention there is provided a pile fabric in the form of an integrated structure comprising a stratum of fibre tufts, a base stratum in the form of a fibrous web and a reinforcing member coextensive with said fibrous web base stratum and in contact with a planar surface thereof, said base stratum containing fibres located in planes normal or substantially so to the planar surfaces of the stratum which fibres project beyond the planar surface of the base stratum which is in contact with the reinforcing member and through the reinforcing member as fibre tufts, thereby providing the fabric with its pile surface.

We have found that pile fabrics possessing superior coverage of the reinforcing material and the fibrous web base stratum by the pile surface, can be obtained, when the fibre tufts, which constitute that surface, efi'loresce, in response to the crimping thereof, into structures having the general appearance of mushrooms and so enhance the spreading of the tufts. Accordingly, in a further aspect of this invention, the fibre tufts are in the form of mushroom-shaped structures with each tuft terminated by a generally dome-shaped cap.

Although the fibre tufts in the pile fabrics provided by this invention in its two aspects discussed hereinbefore, generally exhibit good resistance to extraction, for example, by a pulling action, and the pile surface has a good permanence of form, it is frequently advantageous to set the fibre tufts in the fibrous web base stratum. Accord ingly, in another, and important aspect of this invention, the fibre tufts are set in the fibrous web base stratum.

The pile fabrics of this invention may be made by a method involving the needling, in a needle loom, of a fibrous web located ona reinforcing member, thereby forming a composite needled structure in which fibre tufts extend from the Web into, and through the reinforcing member. When the fibre tufts are crimped and/ or set in the fibrous web base stratum the composite needled structure is subjected to a crimping and/ or a setting treatment.

The effect of needling is to reorientate some of the fibres in the fibrous Web into planes normal or substantially so to the planar surfaces of the Web so that the web contains vertically disposed fibres, which extend beyond a surface of the web into the reinforcing member in contact therewith and beyond a surface of which they project as fibre tufts. Consequently, each fibre tuft represents the extension of vertically disposed fibres embedded in the pile fabrics and to methods of Patented Get. 17, 1 b? fibrous web, and the embedded fibres may be likened both structurally and functionally to the roots of a tree.

The setting treatment to which the composite needled structure may be subjected, which expression embraces any treatment wherein the fibre tufts are secured more firmly to the fibrous web base stratum, confers upon the resulting pile fabric enhanced tuft retention and consequently provides a pile surface possessing a good permanence of form, and a long wear life.

The fibrous Web may be composed of any conventional textile fibre, which term includes filaments and embraces both staple fibres and continuous filaments, for example, natural fibres such, for example, as cotton or wool, man made fibres such, for example, as viscose rayon, cellulose acetate and similar derivatives of cellulose, proteinaceous polymers, polyamides, for example, poly(hexamethylene adipamide), poly(hexamethylene sebacamide), poly(epsilon-caprolactam), and copolymers of these or other polyamides, polyesters, for example, polyethylene terephthalate, polyurethanes, acrylonitrile polymers including copolymers of acrylonitrile, especially with other ethylenically unsaturated monomers such as vinyl chloride, vinyl acetate, methyl acrylate, and vinyl pyridine, vinyl polymers generally for example polyvinyl acetate, polyvinyl chloride, and polystyrene and polymerised hydrocarbons, for example, polyl(ethylene) and poly(propylene) and halogenated derivatives thereof or any mixtures of such fibres. In a particularly useful embodiment of this invention the fibrous web consists of, or contains, heterofilaments which may be in the form of continuous filaments or staple fibres. Conveniently, the heterofilaments comprise at least two synthetic polymer components at least one of which can be rendered adhesive under conditions which leave the other component or components substantially unaffected, the potentially adhesive component occupying at least a portion of the peripheral area of the fibre or filament.

In another embodiment of this invention the fibrous Web may be fabricated from a blend of heterofilament and homofilament. Suitable homofilaments include those listed above. The fibres of which the web is formed may contain pigments, fillers, abrasives and/ or light stabilisers.

The fibrous web may be fabricated in a number of ways, and the method selected in a particular instance, depends to a very large extent on the length of fibres when fibres other than continuous filaments are used. Staple fibre, continuous filament and continuous filament yarn webs are all suitable for use in the present invention.

Staple fibre webs may be prepared, for example, by a Woolen or cotton carding machine or a garnetting machine, in which case the staple fibres are oriented predominantly in one direction. The thin Web obtained from a single card or garnet may be used in accordance with the present invention, but generally it is necessary and desirable to superimpose a plurality of such webs to build up the web to sufiicient thickness for the end use intended. In building up such a Web, alternate layers of carded webs may be disposed with their fibre orientation directions disposed at a certain angle, conveniently with respect to intervening layers. Such cross-laid webs have the advantage of possessing approximately the same strength in at least two directions. Random or isotropic staple fibre Webs may be obtained, for example, *by air-laying staple fibres. Thus, one staple fibre web suitable for use in the method of this invention may be obtained by feeding continuous filaments to a cutter or breaker which discharges the fibres into an air stream produced by the blower. Suitable conduits are provided to guide a suspension of the staple fibres in a current of air to a foraminous surface on which the fibres settle as an interlaced and matted layer, preferably being encouraged to do so by the application of suction n the other side of said surface. The foraminous surface can be in the form of an endless belt which is caused to travel past the place at which the fibres are fed to it, so as to form a continuous layer of indefinite length. Paper-making techniques may also be employed in the making of staple fibre webs.

Continuous filament webs useful in the present invention may be drawn off directly from a spinning (i.e. polymer extrusion) unit, usually as a bundle of filaments or may be supplied from a package or other storage device for yarn already spun.

Continuous filament yarn webs, that is to say, webs in which the filaments are present as multifilaments, may conveniently be prepared in a process wherein freshly spun filaments comprising one or more polymer components are subjected to the action of a high velocity turbulent fluid jet which attenuates and orients the filaments and intermingles them to form a twistless yarn, which yarn is forwarded by the fluid jet and deposited on a receiving surface in a random loopy manner.

When a fabric with enhanced tuft spread, and consequently superior coverage of the reinforcing member and the base stratum, is desired, which fabric may, as previously described, be provided by crimping the fibre tufts, it is necessary that the fibrous web should contain at least a proportion of potentially crimpable fibers, of which heterofilaments, are a particularly useful example.

The needling of a crimped fibrous web into, and through the reinforcing member, may sometimes be found useful in endowing the pile fabric with better developed, and/or other desirable properties, for instance, an increased resiliency.

The reinforcing member present in the pile fabric, which in the method of this invention also provides effective support for the fibrous web during the needling operation, may be any woven fabric or fabric having the structure of a woven fabric, for example, an air-laid scrim fabric. The presence of a woven fabric Within the pile fabric and the protrusion of fibre tufts therethrough enhances the strength and dimensional stability of the fabric by supplementing the contribution made to those properties by the fibre reorientation and entanglement resulting from needling.

The reinforcing member, quite apart from the contri bution which it makes to the strength and dimensional stability of the fabric and the role it plays in the needling operation, when it provides a foundation for the fibrous web, is also important in ensuring good tuft definition and, in this connection, it may be considered as a mould serving to locate, and shape the fibre tufts needled into it and, in those circumstance in which the fibre tufts are set, holding them until the setting treatment has been carried out.

The treatment to which the composite needled structure may be subjected for the setting of the fibre tufts, may take a variety of forms, but we have found that regardless of differences of detail, particularly successful and convenient treatments are those which result in the direct or indirect bonding of fibres in the fibrous web base stratum. As a result of this bonding, the roots of the fibre tufts, that is to say, the vertically isposed fibres embedded in the fibrous web, are fixed in position, and consequently, the fibre tufts are locked in their needled configuration, and so there is enhanced tuft retention in the resulting pile fabric.

This technique of setting the fibre tufts by the bonding of fibres in the fibrous web base stratum ensures that every tuft is anchored in the base stratum and so minimises the tendency of the fibre tufts to be shed during wear, and/or cleaning, and thereby enhances the effective wear life of the fabric.

The particular treatment used to bond fibres in the fibrous web and so set the tuft, may take a number of different forms, and the particular treatment used is largely dependent on the nature of the fibres constituting the fibrous web.

Thus, when the fibres of the web are simple one component fibres, i.e. homofilaments, it is often advantageous to bond fibres in the fibrous web base stratum by the application to the composite needled structure, on the side from which fibres of the fibrous web were needled through the reinforcing member, of an adhesive. After needling, this side of the fabric constitutes the fibrous web base stratum and contains the roots of the fibre tufts together with those fibres of the fibrous web which were not needled through the reinforcing member. The application of an adhesive to the fibrous web base stratum bonds together fibres therein, thereby setting the fibre tufts. The adhesive may also cause coalescence between fibres of the fibrous web and the reinforcing member in contact therewith.

Many different adhesives may be used in this invention. It may be an aqueous or nonaqueous solution, emulsion, or dispersion of an adhesive or of a potentially adhesive material which, upon curing, forms adhesive bonds. As examples of suitable adhesives there may be mentioned rubber (natural or synthetic), polyurethanes, polyvinyl resins such as polyvinyl acetate, polyvinyl alcohol and polyvinyl chloride, and polyamide resins.

The adhesive is conveniently applied in a liquid form to the appropriate surface of the composite needled structure by spraying, for example, through conventional spray nozzles, or by means of a licker-roll. Alternatively the adhesive may be spread over the surface of the fibrous web base stratum in the form of a foam.

The adhesive may take the form of a bonding agent incorporated in the fibrous web, the bonding agent being potentially adhesive under conditions which do not effect fibres of the web. For example, the binding agent may have a softening point below that of fibres present in the web and hence can be rendered adhesive i.e. activated, by heat. In such instances the treatment may conveniently involve heating to a temperature above the softening point of the extraneous bonding agent but below that of the fibres of the fibrous web. The heating may conveniently be carried out by passing the composite needled structure over a hot drum in such a manner, that only the surface of the structure on the side opposite the side carrying the fibre tufts is brought into contact with the drum. The bonding agent may be capable of being activated by some suitable chemical means, when the treatment may conveniently comprise application of a suitable chemical medium to the fibrous web side of the composite needled structure.

The bonding agents which may be activated by heat or chemical means are frequently in the form of powders, fiock fibres or staple fibres. When the web contains heterofilaments of the type comprising at least two synthetic polymer components, it is often convenient to have present in the heterofilament at least one component which can be rendered adhesive under conditions which leave the other component or components non-adhesive, the potentially adhesive component being arranged to form at least a portion of the periphery of the filament, for then the treatment to bond fibres in the fibrous web base stratum, and thereby set the fibre tufts, need involve merely activation of the potentially adhesive component.

Particularly suitable heterofilaments for use in the method of this invention are those in which the potentially adhesive component has a lower softening point than the other component or components and can thus be activated, and the tufted fibres thereby secured, by a treatment involving heating. As examples of such heterofilaments we may mention poly(hexamethylene adipamide)-poly(epsilon-caprolactam)(nylon 66/6) filaments in which poly (epsilon-caprolactam) is the lower melting component and poly(hexamethylene adiparnide)-poly(ornega-aminoundecanoic acid)(nylon 66/ ll) filaments in which the poly(omega-aminoundecanoic acid) component has the lower melting point, and poly(hexamethylene adipamide) poly(hexamethylene adipamide)-poly(epsilon caprolactam) copolymer filaments in which the copolymer component has the lower melting point. Heterofilaments other than those based on the polyamide system may also be used. Thus, heterofilaments formed, for example, from polymers based on polyesteramides, polyesters, polyolefins and polyurethanes may be suitable.

The potentially adhesive component of the heterofilament may be such, that it can be activated, and the fibre tufts thereby set, by treatment using suitable chemical media, for example, by treatment with an essentially non-aqueous formaldehyde solution. An example of such a heterofilament is one consisting of poly(hexamethylene adipamide) as one component and an 80/20 random copolymer of poly(hexamethylene adipamide) and poly (epsilon caprolactam) as the other component, in which the copolymer component can be activated by means of a hot ethylene glycol solution of formaldehyde, which leaves the poly(hexamethylene adipamide) component substantially non-adhesive.

The relative amounts of the adhesive and non-adhesive components constituting the heterofilaments can be varied to suit the type of pile fabric required, having regard to the physical properties desired therein.

The incorporation in the fibrous web of at least a certain proportion of heterofilaments of the type previously described, permits the tufts to be set in a convenient and efiicient manner, as a result of what is in essence an in situ development of a bonding agent through the activation of a potentially adhesive component of the heterofilaments. The activation of the potentially adhesive component is normally accomplished, without destruction of the fibrous character of the heterofilament, for the activated component is maintained in contiguous association with the other component, and this retention of fibrous character is believed to be of importance in properties such as tuft definition and retention, properties which contribute toward determining the permanence of the pile surface, and also the dyeability of the resulting pile fabric. In addition, the use of heterofilaments allows precise control of the quantity of binder and uniform disposition throughout the fibrous web to be readily attained.

Furthermore, when heterofilaments are employed in the fibrous web, crimping of fibres therein is readily and conveniently effected. For example, it is possible to crimp the heterofilaments in the same treatment as is used to activate the potentially adhesive component, when the tufts efiloresce into mushroom-shaped structures and spread out so providing for more effective concealment of the reinforcing member and the fibrous web base stratum.

The pile fabrics of this invention find particular application as floor-covering materials, but they are diversified in regard to the end uses in which they can be employed, for example, they are useful, furniture, for instance, upholstery, fabrics.

The invention is further described by reference to the following illustrative examples and the accompanying drawings wherein:

FIGURE 1 is a diagrammatic view sequentially illustrating a simplified embodiment of a method of making a pile fabric according to this invention;

FIGURE 2 is a diagrammatic cross-sectional view of the layered assembly of FIGURE 1 prior to needling;

FIGURE 3 is a diagrammatic cross-sectional view of the composite needled structure of FIGURE 1;

FIGURE 4 is a diagrammatic cross-sectional view of the composite needled structure of FIGURE 1 after fibres therein have been crimped.

In referring to the other figures: In FIGURE 1 there is shown a supply roll for an open weave material such as hessian 11, which is unwound from left to right on the surface of an endless belt 12. Layer 13 so formed is intended to 'be used as the reinforcing member in the formation of the pile fabric product. Reference numeral 14 designates a supply roll of a fibrous web 15 which is being continuously superimposed, with the aid of a roller. 16, as a layer 17 upon the hessian 13 and moved at the same rate and in the same direction as the hessian. The layered assembly which is shown in FIGURE 2, and which comprises fibrous web 17 on hessian 13, is then fed to a needle loom, indicated generally by reference numeral 18, of conventional design.

Needle loom 18 comprises a horizontal surface 19 and a needle board 20. The needle loom 18 reciprocates needles into, and out of, the fibrous web, and reorients some of the fibres of the web into planes normal or substantially so to the planar surfaces thereof, the vertically disposed fibre projecting beyond a planar surface, into, and through, the hessian as fibre tufts.

The composite needled structure 21 so formed is shown in FIGURE 3. It consists of three superimposed strata; a fibrous web base stratum 27, the hessian layer 13 as the reinforcing member and a stratum of fibre tufts 28 which provide the pile surface of the resulting fabric, and which represent the projections beyond a planar surface 29 of the base stratum and through the hessian 13, of vertically disposed fibres 30A (the roots) embedded within the base stratum. The base stratum contain not only fibres 30 but also other fibres 31B arranged in plane predominantly normal to the plane of the vertically disposed fibres 30A. The hessian layer 13, in addition to its role in reinforcing the pile fabric, and supporting the fibrous web layer 17 in the needling operation, also serves as a mould for locating, shaping and holding the fibre tufts needled into it.

The composite needled structure 21 is then subjected to a treatment, for example, immersion in boiling water to crimp fibres therein, and the means employed for this purpose is indicated by reference numeral 22 in FIGURE 1. The development of crimp in the fibre tufts 28, as can be seen in FIGURE 4, results in an efiiorescence thereof, with a consequent diffusion or spreading out of the tufts over the surface, and in doing this, they adopt a more rounded configuration. Indeed, individual crimped tufts, with a short vertical stem portion 31 standing proud above the hessian layer 13, terminating in a rounded cap 32, have the general appearance of a mushroom.

The pile fabric 23 emerging from the crimping treatment is then carried through a zone, indicated by reference numeral 24 in FIGURE 1, wherein means, for example, an oven, are employed to set the fibre tufts 28 in the fibrous web base stratum 27. The pile fabric 25 so formed is wound up on a product reel 26.

filament consisting of equal proportions by weight of poly(hexamethylene adipamide) as one component and an /20 random copolymer of poly(hexamethylene adipamide)/poly(epsilon caprolactam) as the other, the two components being arranged in side-by-side relationship, was air-laid by means of a Proctor-Schwartz Duo- Form air-laying machine, to produce a fibrous web having a weight of approximately 15 ounces per square yard.

This fibrous web was laid on a sheet of a hessian fabric, weighing approximately 10 ounces per square yard, and the layered assembly was then needle punched by means of a conventional single-bed needle loom supplied by William Bywaters Limited, Leeds, equipped with 25 gauge standard barb needles. The assembly was run through the needle loom with the hessian beneath, and in contact with, the web, which it effectively supported during the needling operation, so that the needles penetrated first the web and then the hessian. The depth of needling was adjusted so that the needles penetrated to a depth of A2 inch, and the assembly was passed several times through the needle loom until a needling density of approximately 600 punches per square inch had been effected. In consequence of the needling operation, a high proportion of fibres in the fibrous web were reoriented into planes normal, or substantially so, to the planar surfaces of the web, these vertically disposed fibres being extended beyond a planar surface of the web into, and through, the hessian to appear on the other side thereof as fibre tufts. The tufts stood up above the hessian a distance of about A inch so providing the pile fabric with a pile surface having a pile height of about inch.

The pile fabric was composed of three superimposed strata, all of which could be recognised in a cross-sectional view thereof. The pile surface of the fabric was composed of fibre tufts of the fibre tuft stratum and the fibrous web base stratum formed the base. interposed between these two strata, and in contact with a planar surface of the latter, was the hessian reinforcing member. The pile fabric had an attractive appearance and a pleasant warm handle.

The fabric was then dyed by immersion in a dye-bath containing a disperse dye with boiling water as the disperse medium. Contact with the boiling liquid caused the heterofilaments to crimp, and the crimp development lead to an effiorescence of the fibre tufts, which spread out and formed mushroom-shaped structures. The spreading out of the fibre tufts in this manner, was reflected in the denser pile surface so obtained, with a corresponding enhanced coverage of the hessian reinforcing member and the fibrous web base stratum, and, indeed, the hessian reinforcing member and the base stratum were completely hidden from visual discernment. Furthermore, the conversion of the tufts from predominantly vertically disposed structures into more diffuse and rounded mushroom-shaped structures imparted to the pile fabric better wearing qualities, for instance, the spring-back, that is to say, the ability of the pile surface to return to its original conformation after deformation, for example, by placing weight thereon, was much improved.

Although this pile fabric had a good tuft retention, this property and others, for example, the abrasion resistance, could be improved by setting the fibre tufts in the fibrous web base stratum. This was accomplished by passing the pile fabric through an Efco conveyorised oven operating at a throughput of feet per minute and a temperature of 230 C. At this temperature, the copolymer component of the heterofilaments was activated and developed its adhesive characteristics. In this condition it bonded together fibres in the fibrous Web base stratum at points where they crossed-over or met, and thereby set the fibre tufts in the base stratum. The resulting pile fabric made a very hard wearing floor-covering material.

The pile surface of the fabric is formed of fibre tufts which, as a result of crimp development, have spread out in planes substantially parallel to the plane of the fabric, and merged one with another to an extent such that individual tufts can be distinguished only with difficulty, thereby providing the fabric with a dense, resilient and hard wearing pile which completely conceals from the eye the hessian. The fibre tufts are firmly secured by the setting treatment in the fibrous web base stratum which serves as a resilient backing for the fabric, which is particularly valuable when it is utilised as a floor-covering material.

The pile fabric of this example at any stage of its development possessed an excellent strength, since the contribution mode thereto by the reoriented and entangled needled fibres, was complemented by that due to the hessian reinforcing member.

Example 2 A quantity of 9 denier, two and a half inch staple fibre, formed from a fully drawn heterofilament comprising equal proportions by weight of poly(hexamethylene adipamide) as one component and poly(hexamethylene adipamide)-poly(epsilon caprolactum)(80/20) copolymer as the other component, the two components having a sideby-side relationship and the heterofilament containing 9 crimps per inch was carded using 21 Shirley miniature card, and the laps so formed, laid on top of each other with successive laps disposed at an angle of with respect to the previous lap, thereby forming a cross-laid web having a weight of approximately 6 ounces per square yard.

The heterofilament cross-laid web was then further crimped by immersion of the web in boiling water. As a result of this boiling Water treatment, the web shrunk into a half-inch thick dense web having a weight of 18 oz./yd. This web was then laid on a hessian fabric as the reinforcing member, the hessian travelling on an endless moving belt. The layered assembly was then advanced to a single bed needle-loom where it was needle punched as in Example 1, except that the assembly was passed only once through the loom, the speed therethrough being adjusted to effect 25G punches per square inch. As a result of this needling many fibres in the fibrous web were punched into, and through, the hessian to appear as tufts on the surface of the hessian opposite to that on which the fibrous web was originally located. Rubber latex solution was applied to the surface of the needled fabric opposite to the tufted surface i.e. to the fibrous web base stratum. The latex on setting, acted as an adhesive which caused fibres in the fibrous web base stratum, including the tuft roots located therein, to bond together thereby setting the fibre tufts in the fibrous web base stratum. The latex on setting also bonded the fibres of the fibrous base stratum to the hessian supporting material thereby enhancing the overall integrity of the pile fabric product. The latex was set simply by drying at a temperature of approximately C. in a conveyorised oven. The product was a pile fabric of good strength and having an uncut tuft height of 7 inch, through which the hessian reinforcing member was not visible even on considerable flexing, and was eminently suitable for use as a hard-wearing carpet.

The presence of crimped fibres in the fibrous web base stratum gave the fabric additional resiliency and obviated the need for any backing, when used as a carpet.

The abrasion resistance of the pile fabric and the tuft retention could be enhanced by heating the fabric for a period of 3-4 minutes at a temperature of 230 C. prior to latex application so as to activate the copolymer component of the heterofilament and bend together fibres in the base stratum.

Example 3 A continuous filament yarn web having a weight of approximately 8 ounces per square yard and composed of heterofilaments consisting of equal proportions by weight of poly(hexamethylene adipamide) as one component and (an 80/20 random copolymer of poly(hexamethylene adipamide)-poly (epsilon caprolactam) as the other, the two components being arranged in a side-'by-sicle relationship, was made by a process wherein freshly psun heterofilaments, were subjected to the action of a high velocity turbulent fluid jet, which attenuated and oriented the heterofilaments and intermingled them to form a twistless yarn, which yarn was forwarded by the fluid jet and deposited on a hessian sheet, supported on an endless moving belt, in a random loopy manner. The layered assembly so formed was needle-punched as in Example 1, except that regular 32 gauge barb needles were used, and the needle penetration was adjusted to give a depth of needling of inch. The composite needled fabric was then dyed by immersion in a dye-bath of a disperse dye using boiling water as the disperse medium. Crimping of the fibre tufts, with a spreading thereof, was also effected in the dyeing operation. The dyed pile fabric resembled a conventional tufted carpet in appearance, and made a useful floor-covering material. As with all the pile fabrics of this invention derived from fibrous webs consisting of,

or containing, heterofilaments, abrasion resistance and tuft retention could be developed to a superior degree by activating the potentially adhesive component so as to bond fibres in the fibrous web base stratum and thereby set the fibre tufts. With the instant pile fabric this could be achieved by heating the pile fabric for a period of 3-4 minutes at a temperature of 230 C.

Example 4 A mixture of equal proportions by weight of 3 denier, one and a half inch poly(propylene) staple fibres and 6 denier, two inch poly(hexamethylene adipamide) staple fibres was carded on the Shirley miniature card and the laps so formed cross-laid with successive laps dispersed at 90 with respect to the previous lap into a web having a weight of approximately 10 ounces per square yard. This cross-laid web was then laid on a hessian fabric and the layered assembly advanced through a needle loom in which it was needled as in Example 1, except that 32 gauge regular barb needles were employed and the penetration of the needles was adjusted to give a depth of needling of 1 /2 inches. The effect of the needling Operation was to reorientate a high proportion of fibres in the fibrous web into planes normal to the planar surfaces thereof, and these vertically disposed fibres protruded, as fibre tufts, through the hessian reinforcing member an appreciable distance.

The fibre tufts formed a pile surface, the density of which was such, that the hessian was hidden completely from view, wherein the pile height was adequate.

A pile fabric having a superior tuft retention and better abrasion resistance was made from the basic pile fabric by heating the latter in an oven at a temperature of 210 C. for a period of 2-4 minutes, when the poly(propylene) fibres fused and, in that condition, bonded fibres in the fibrous web, thereby setting the tufts. The resulting pile fabric made a hard wearing floor-covering material of good dimensional stability. In its application as a floorcovering material the instant pile fabric possessed the additional advantage of reversibility, since both surfaces were fibrous in character, although the fibre tuft surface would be the normal wearing surface.

Example 5 A quantity of 3 denier, one and a half inch poly(ethyleneterephthalate) staple fibres was carded using a Shirley miniature card and the lap so formed cross-laid, with successive laps disposed at an angle of 90 with respect to the previous lap, into a web having a weight of approximately 10 ounces per square yard. The cross-laid web was then laid on a sheet of a hessian fabric and the layered assembly needle-punched as in Example 1, except that 32 gauge regular barb needles were employed and the penetration of the needles was adjusted to give a depth of needling of 1 /2 inches. As a result of this needling a high proportion of the fibres in the fibrous web were reoriented and punched through the hessian, to appear on the side of the hessian opposite so that on which the fibrous Web had been laid. Rubber latex solution was applied to the surface of the composite needled fabric opposite to the fibre tuft surface, i.e. to the fibrous web base stratum. The latex acted as an adhesive and served to bond fibres in the fibrous web base stratum, including the roots of the fibre tufts, and thereby setting the fibre tufts in the base stratum. The latex also bonded fibres in the fibrous web base stratum to the hessian, and its overall effect was to ensure each fibre tuft was secured in position. The product was a pile fabric having good dimensional stability and strength in addition to good tuft retention. It was very suitable for application as a floor-covering material.

Although representative embodiments of this invention have been specifically described, it is not intended or desired that the invention be limited solely thereto as it will be apparent to those skilled in the art, that modifications and variations may be made without departing from the It) spirit and scope of the invention as defined in the appended claims.

What we claim is:

1. A pile fabric in the form of an integrated structure comprising a stratum of fibre tufts, a base stratum in the form of a fibrous web and a reinforcing fabric coextensive with said fibrous web base stratum and in contact with a planar surface thereof, said base stratum containing at least a proportion of composite fibres comprising at least two fibre-forming synthetic polymeric components arranged in distinct zones across the cross-section of each fibre, each component being continuous along the length of each fibre and at least one, and less than all, of the components being potentially adhesive and located so as to form at least a portion of the peripheral surface of each fibre and said base stratum containing fibres located in planes at least substantially normal to the planar surfaces of the stratum, which fibres project beyond a planar surface of the base stratum and through the reinforcing fabric as fibre tufts, thereby providing the fabric with its pile surface, said composite fibres being adhesively bonded to contiguous fibres in the structure through the agency of said potentially adhesive component thereby securing the tufts in the structure.

2 A pile fabric according to claim 1 in which tufts are crimped, said crimp resulting from a difference in physical properties of the components of the composite fibres.

3. A pile fabric according to claim 1 in which the composite fibres contain two components, the potentially adhesive component being poly(omega-aminoundecanoic acid).

4. A pile fabric according to claim 1 in which the composite fibres contain two components, the potentially adhesive component being poly(epsilon caprolactam).

5. A pile fabric according to claim 3 in which the other component is poly(hexamethylene adipamide).

6. A pile fabric according to claim 4 in which the other component is poly(hexamethylene adipamide).

7. A pile fabric according to claim 2 in which the composite fibres contain two components, the potentially adhesive component being poly(omega-aminoundecanoic acid).

8. A pile fabric according to claim 2 in which the composite fibres contain two components, the potentially adhesive component of the composite fibres being poly (epsilon caprolactam).

9. A pile fabric according to claim 7 in which the other component is poly(hexamethylene adipamide).

10. A pile fabric according to claim 8 in which the other component is poly(hexamethylene adipamide).

11. A method of making a pile fabric which comprises forming a fibrous web containing at least a proportion of composite fibres comprising at least two fibre-forming synthetic polymeric components arranged in distinct zones across the cross-section of each fibre, each component being continuous along the length of each fibre and at least one, and less than all, of the components being potentially adhesive and located so as to form at least a portion of the peripheral surface of each fibre, laying said fibrous web on a reinforcing fabric, needling, in a needle loom, said fibrous web and said reinforcing fabric thereby forming a composite structure in which fibre tufts extend from the web into, and through the reinforcing fabric and subjecting said structure to a treatment to render adhesive said potentially adhesive component thereby adhesively bonding the composite fibres to contiguous fibres in the structure and securing said fibre tufts in the structure.

12. A method of making a pile fabric as claimed in claim 11 in which said web is formed of composite fibres which also possess potential crimp as a result of a difference in the physical properties of their components and in which said treatment also develops said crimp in said composite fibres.

13. A method of making a pile fabric as claimed in claim 11 in which said structure is subjected to a heat 1 1 1 .2 treatment to render adhesive said potentially adhesive of a suitable chemical medium to render adhesive said pocomponent. tentially adhesive component and develop said crimp.

14. A method of making a pile fabric as claimed in References Cited claim 11 in which said structure is subjected to the action of a suitable chemical medium to render adhesive said potentially adhesive component. 2,331,321 10/1943 Heaton 16181 15. A method of making a pile fabric as claimed in 29703 2/1961 Morgenstem 156-148 X claim 12 in which said structure is subjected to a heat FOREIGN PATENTS treatment to render adhesive said potentially adhesive 10 326 1 3 12 1959 Great Britain component and develop said crimp.

16. A method of making a pile fabric as claimed in ALEXANDER WYMAN, Primary Examine!- claim 12 in which said structure is subjected to the action R H R SS Assistant Examiner.

UNITED STATES PATENTS 

1. A PILE FABRIC IN THE FORM OF AN INTEGRATED STRUCTURE COMPRISING A STRATUM OF FIBRE TUFTS, A BASE STRATUM IN THE FORM OF A FIBROUS WEB AND A REINFORCING FABRIC COEXTENSIVE WITH SAID FIBROUS WEB BASE STRATUM AND IN CONTACT WITH A PLANAR SURFACE THEREOF, SAID BASE STRATUM CONTAINING AT LEAST A PROPORTION OF COMPOSITE FIBRES COMPRISING AT LEAST TWO FIBRE-FORMING SYNTHETIC POLYMERIC COMPONENTS ARRANGED IN DISTINCT ZONES ACROSS THE CROSS-SECTION OF EACH FIBRE, EACH COMPONENT BEING CONTINUOUS ALONG THE LENGTH OF EACH FIBRE AND AT LEAST ONE, AND LESS THAN ALL, OF THE COMPONENTS BEING POTENTIALLY ADHESIVE AND LOCATED SO AS TO FORM AT LEAST A PORTION OF THE PERIPHERAL SURFACE OF EACH FIBRE AND SAID BASE STRATUM CONTAINING FIBRES LOCATED IN PLANES AT LEAST SUBSTANTIALLY NORMAL TO THE PLANAR SURFACES OF THE STRATUM, WHICH FIBRES PROJECT BEYOND A PLANAR SURFACE OF THE BASE STRATUM AND THROUGH THE REINFORCING FABRIC AS FIBRE TUFTS, THEREBY PROVIDING THE FABRIC WITH ITS PILE SURFACE SAID COMPOSITE FIBRES BEING ADHESIVELY BONDED TO CONTIGUOUS FIBRES IN THE STRUCTURE THROUGH THE AGENCY OF SAID POTENTIALLY ADHESIVE COMPONENT THEREBY SECURING THE TUFTS IN THE STRUCTURE. 